The results, published in the British Journal of Nutrition, found the extract reduced the percentage of mice with diet-induced severe steatosis (fatty liver), hypercholesterolaemia and hyperglycaemia.
Total plasma cholesterol and glucose levels were significantly lower in the blackcurrant group compared to the control, yet plasma triglyceride (TAG) level were not significantly different.
The researchers from the University of Connecticut in the US gave 24 mice either a control diet high in cholesterol (0.25%) and fat (15%) or the same diet supplemented with blackcurrant extract.
The extract contained 25% anthocyanins and 40% polyphenols and the dose equated to a daily human consumption of about 540 mg of the extract and 135 mg anthocyanins.
The researchers said such an ingredient could help reduce disease risk since dyslipidaemia and hyperglycaemia were likely to contribute to metabolic diseases. The danger of obesity, they said, lay not just in the condition itself but the progression to things like type 2 diabetes, cardiovascular and non-alcoholic fatty liver disease.
Extract and expressions
They found the expression of the PCSK9 (proprotein convertase subtilisin/kexin type 9) was significantly decreased in the livers of mice fed the blackcurrant extract. This enzyme played a role in the degradation of the low-density lipoprotein (LDL) receptor.
“Induction of LDL receptor expression and activity in the liver is one of the preventive/therapeutic goals to lower circulating cholesterol,” the researchers wrote.
Popular cholesterol-lowering drugs statins work by indirectly increasing LDLR expression.
They said another important finding was the impact the supplementation had on the enhancement of energy use in the skeletal muscle, which could explain the reduction of fasting glucose and liver steatosis.
Source: British Journal of Nutrition
Published online ahead of print, doi:10.1017/S0007114515001105
“Polyphenol-rich blackcurrant extract exerts hypocholesterolaemic and hypoglycaemic effects in mice fed a diet containing high fat and cholesterol”
Authors: T. Benn, B. Kim, Y.K. Park, Y. Yang, T. X. Pham, C. S. Ku, C. Farruggia, E. Harness, J. A. Smyth and J. Y. Lee